Summary: Stacey is in Liverpool to meet 52 year-old Richard, who is on a life-long mission to discover the identity of his father. Sixty two year-old Janet has spent her life wondering if a rumour is true that she might have a secret sister. Glen’s mother never knew where his father was from, only that he wasn’t white.

Summary: Liverpool-born Maureen is wondering if her father was an African-American GI who fell in love with her mother during the Second World War - which could mean she has family in the US. She’s also curious why her three sons are so musically talented and if the secret may lie in her DNA. 79-year-old Jackie grew up in a Nazi concentration camp as a Jewish orphan and wants to know why he survived. Was his dad actually a Nazi? And did any of his birth family escape the Holocaust?

Summary: Forty-six-year-old Mel only found out as a teenager that she was conceived using a sperm donor. Now she wants to see if she can find her biological father’s identity by decoding her DNA - and discovers far more than she ever expected. Fi always knew she was adopted. What she didn't know until later in life was that her father murdered her birth mother. Fi wants to know if it is possible to inherit a 'murder gene'. Bahaa escaped the war in Syria but now wants to know if he carries a potentially deadly mutation in his DNA.

Summary: 38-year-old Clare was always told that her father was a British soldier stationed in Belfast during the Troubles. Now, Clare wants to solve the mystery of his identity. Leigh only discovered that he might have a secret sister after his mum passed away. He now wonders if his sister is still alive. It was only when Jenna and Ryan were pregnant that they realised they both carry a genetic mutation that could be deadly if passed on to their kids. They’re hoping that DNA testing can help.

Summary: Georgina was conceived 34 years ago when her mum had a holiday romance with a Portuguese waiter. She’s now wondering if her father is still alive. Matthew grew up never knowing his father’s identity and wants to know if his ancestry is actually Caribbean. Michaela and Richie only realised they could pass down the genetic disorder 'bubble boy disease' when they had their son Arlo. Now they’re testing their second child’s DNA to discover if he has to undergo life-saving gene therapy.

Summary: Stacey meets five sisters in Lancashire who only found each other as adults. They know they all share the same mum but want to find out if they also have the same father. Luke was a sperm donor as a university student in the late 1980s. He’s now come forward to find out if any potential children might be looking for him. After losing their mother to cancer, identical twins Diane and Louise want to test their DNA to discover if they both carry the cancer-causing BRCA genetic mutation.